Acid Zirconium Phosphate and Alkaline Hydrous Zirconium Oxide Materials For Sorbent Dialysis

• US 20100078387A1
• Filed: 09/04/2009
• Published: 04/01/2010
• Est. Priority Date: 09/30/2008
• Status: Active Grant

• Current Assignee: Fresenius Medical Care Holdings Incorporated (Fresenius SE & Co. KGaA)
• Original Assignee: Fresenius Medical Care Holdings Incorporated (Fresenius SE & Co. KGaA)
• Inventors: Wong, Raymond June-Hin
• Granted Patent: US 8,409,444 B2
• Time in Patent Office: Days
• US Class Current: 210/656
• CPC Class Codes: A61M 1/1696 with dialysate regeneration
• CPC Class Codes: B01J 39/12 Compounds containing phosphorus
• CPC Class Codes: B01J 41/10 Inorganic material
• CPC Class Codes: B01J 47/04 Mixed-bed processes

Abstract

A combination of acid zirconium phosphate and alkaline hydrous zirconium oxide are utilized as ion-exchange materials, for example, in sorbent dialysis. The combination provides for dialysate regeneration while maintaining constant and controlled levels of Na⁺, HCO₃⁻, and pH.

Claims

1. A sorbent cartridge comprising a combination of acid zirconium phosphate (AZP) and alkaline hydrous zirconium oxide (NaHZO) in the sorbent cartridge.

2. The sorbent cartridge of claim 1, wherein the cartridge comprises at least two layers, wherein at least one of the layers comprises the combination of AZP and NaHZO.

3. The sorbent cartridge of claim 1, wherein the AZP and the NaHZO comprise particles having an average grain size of from about 25 microns to about 60 microns.

4. The sorbent cartridge of claim 1, wherein the combination has a pH of from about 3 to about 7.

5. The sorbent cartridge of claim 1, wherein the combination has a pH of from about 3.5 to about 4.

6. The sorbent cartridge of claim 1, wherein the combination has a pH of from about 5.5 to about 6.

7. The sorbent cartridge of claim 1, wherein the AZP and NaHZO are each present in the combination in an amount to produce an NaHZO:

AZP weight ratio of from about 0.2;

0.8 to about 0.8;

0.2.

8. The sorbent cartridge of claim 7, wherein the NaHZO:

AZP weight ratio is from about 0.5;

0.5 to about 0.6;

0.4.

9. The sorbent cartridge of claim 7, wherein the NaHZO:

AZP weight ratio is about 0.4;

0.6.

10. The sorbent cartridge of claim 7, wherein the NaHZO:

AZP weight ratio is from about 0.22;

0.78 to about 0.33;

0.67.

11. The sorbent cartridge of claim 1, further comprising zirconium phosphate (ZrP).

12. The sorbent cartridge of claim 11, wherein the ZrP is present as a layer in the sorbent cartridge.

13. The sorbent cartridge of claim 11, wherein the ZrP has a pH of from about 3 to about 7.

14. The sorbent cartridge of claim 11, wherein the ZrP has a pH of from about 3.5 to about 4.

15. The sorbent cartridge of claim 11, wherein the ZrP has a pH of from about 5.5 to about 6.

16. The sorbent cartridge of claim 1, further comprising activated carbon, immobilized urease, or combinations thereof.

17. The sorbent cartridge of claim 16, wherein the activated carbon and the immobilized urease are each present as a layer in the sorbent cartridge.

18. The sorbent cartridge of claim 1, wherein the sorbent cartridge is configured to restore the balance of Na⁺ and HCO₃⁻

in spent dialysate to levels found in fresh dialysate.

19. A method to regenerate or purify spent dialysate comprising passing the spent dialysate through the sorbent cartridge of claim 1.

20. A method to regenerate or purify spent dialysate comprising passing the spent dialysate through the sorbent cartridge of claim 11.

21. The method of claim 19, wherein the method comprises restoring the spent dialysate to original balance of Na⁺ and HCO₃⁻

contents found in fresh dialysate.

22. The method of claim 19, wherein the method comprises restoring the spent dialysate to original pH of fresh dialysate.

23. The method of claim 19, wherein the regenerated dialysate has a pH from about 6.8 to about 7.4.

24. The method of claim 19, wherein the regenerated dialysate has a Na⁺ content from about 110 mEq/L to about 150 mEq/L.

25. The method of claim 19, wherein the regenerated dialysate has a HCO₃⁻

content from about 25 mEq/L to about 35 mEq/L.

26. The method of claim 19, wherein the dialysate is regenerated without generating CO₂ gas bubbles.

27. The method of claim 19, wherein the dialysate is regenerated without releasing Na⁺ to the dialysate.

28. The method of claim 19, wherein NaHCO₃ present in spent dialysate is converted by the AZP to form carbonic acid and CO₂, and the carbonic acid and the CO₂ are converted by the NaHZO to form NaHCO₃.

29. A method of preparing purified fresh dialysate for dialysis comprising passing the dialysate through the sorbent cartridge of claim 1.

30. The method of claim 29, wherein the dialysate comprises tap water.

31. An apparatus for conducting dialysis comprising the sorbent cartridge of claim 1, and a dialyzer in fluid communication with the sorbent cartridge, wherein spent dialysate passes from the dialyzer to and through the sorbent cartridge.

32. The apparatus of claim 31, wherein the spent dialysate is spent hemodialysate, spent peritoneal dialysate, or combinations thereof.

33. The apparatus of claim 31, wherein the dialyzer is in fluid communication with the blood of a patient.

34. A dialysis system comprising the sorbent cartridge of claim 1 and a source of spent dialysate, wherein the source of the spent dialysate is in fluid communication with the sorbent cartridge and the spent dialysate passes to and through the sorbent cartridge.

35. The dialysis system of claim 34, wherein the spent dialysate passes through the sorbent cartridge at a rate of about 100 ml/min to about 550 ml/min.

36. The dialysis system of claim 34, wherein the spent dialysate is regenerated.

37. The dialysis system of claim 36, wherein the spent dialysate is regenerated to a pH level about equal to that of fresh dialysate.

38. The dialysis system of claim 36, wherein the spent dialysate is regenerated to a Na⁺ level and HCO₃⁻

level about equal to that of fresh dialysate.

39. The dialysis system of claim 36, wherein the spent dialysate is regenerated without formation of CO₂ bubbles.

40. The dialysis system of claim 36, wherein a uniform level of Na⁺ is maintained in the spent dialysate while being regenerated.